chars = [ 'a', 'b', 'c', 'd', 'e' ];

SCR.innerHTML="";
for (var i=0;i<200;i++)    {
    SCR.innerHTML+="<span>"+chars[i%5]+"</span>";
}


LAYER1.addTo("anim1", function()    {
    $$('span').forEach( function(e)    {
        e.setTransform({ dx: Math.random()*400, dy: Math.random()*400});
    });
});